Introduction of a concept of a flexible Ethernet (FlexEth) provides a feasible evolution direction for virtualization of an Ethernet physical connection. In the FlexEth, one or more physical connections are bound by using cascading to constitute a physical connection group, to obtain a bandwidth resource pool. Total bandwidth resources of the bandwidth resource pool are a sum of bandwidth resources of all physical connections in the physical connection group. From another perspective, the physical connection group may be considered as a high speed logical connection that is implemented between a transmit end and a receive end. The logical connection has a total bandwidth of the bandwidths of the physical interface connections that are bound using cascading. In the FlexEth, the bandwidth resources of the physical connection group are further divided into several timeslots using time division. Several virtual connections are supported by binding the timeslots using cascading, thereby providing a powerful flexibility characteristic for data transmission in the Ethernet.
Data is transmitted over each physical connection in the physical connection group using a data frame as a period. One subframe is used as an example. The subframe includes an overhead code block at the beginning part, and then 1024 groups of information code blocks closely follow. Each group of information code blocks usually includes 20 code blocks that respectively correspond to bandwidth resources of 20 timeslots obtained using time division. When transmitting a service stream using a virtual connection supported by the physical connection group, the transmit end and the receive end need to determine, based on a timeslot configuration table used by each physical connection in the physical connection group, a timeslot bandwidth resource that belongs to the virtual connection, and then use the timeslot bandwidth resource to transmit the service stream to a receive end. In one system, a 16-bit Client field is defined in an overhead area of a physical connection, and is specially used to transmit content of the timeslot configuration table, so that the receive end can correctly restore the service stream.
However, the timeslot configuration table used by the physical connection does not always change, and information transmitted in a field specially defined for the timeslot configuration table in the overhead area may be repeated or unwanted information. In addition, the timeslot configuration table of the physical connection is excessively large, and in a current system, 40 basic frame periods are needed to transmit content of a complete timeslot configuration table to the receive end. Therefore, transmission efficiency is low.